"Carnivale" debuted to 5.3 million viewers, making it the most-watched series opener ever on HBO. "Six Feet Under" was the previous record-holder, with about 5 million viewers for its 2001 premiere.

The new show may be hard-pressed to duplicate those numbers, however, when it moves to 9 p.m. ET this week. "Carnivale" will have to do without the "Sex and the City" lead-in and will face more competition as the broadcast networks begin their fall season.